System and method of controlling fuel injection pressure in an engine having an in-cylinder pressure sensor

Abstract

A method of operating an internal combustion engine is provided. An in-cylinder pressure within a cylinder of the engine is determined. A fuel injection pressure from a fuel injector disposed within the cylinder is determined. A ratio of the in-cylinder pressure within the cylinder and the fuel injection pressure is compared to a stored threshold value. The fuel injection pressure is adjusted based upon the comparison of the ratio of the in-cylinder pressure within the cylinder and the fuel injection pressure to the stored threshold value.

What is claimed is: 
     
       1. A method of operating an internal combustion engine having a plurality of cylinders, comprising:
 providing a pressure sensor within a cylinder of the engine for generating a signal representative of the pressure within the cylinder in which the pressure sensor is disposed; 
 providing a fuel injector in communication with the cylinder having variable injection pressure capability; 
 determining a fuel injection pressure of a fuel injector disposed within the cylinder and generating a signal representative of the fuel injection pressure; 
 a fuel injector controller operatively connected with the pressure sensor and fuel injector for receiving the signals from the pressure sensor representative of the pressure within the cylinder and for receiving the signals representative of the fuel injection pressure: 
 the fuel injector controller configured to perform a calculation of the ratio of the in-cylinder pressure signals and the fuel injection pressure signals; 
 providing a database of stored threshold values of the ratio of the in-cylinder pressure signals to fuel injection pressure signals; 
 the fuel injection controller also configured to operate the injector to inject fuel into the cylinder at a predetermined fuel injection pressure based on a stored threshold value; 
 the fuel injection controller also configured to compare the ratio of the in-cylinder pressure and the fuel injection pressure; and 
 the fuel injector controller adjusting the fuel injection pressure based upon the comparison of the ratio of the in-cylinder pressure within the cylinder and the fuel injection pressure to the stored threshold value.